Wikipedia said:In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an "acceptable" focus. There are two commonly used definitions of hyperfocal distance, leading to values that differ only slightly:
Definition 1: The hyperfocal distance is the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp; that is, the focus distance with the maximum depth of field. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.
Definition 2: The hyperfocal distance is the distance beyond which all objects are acceptably sharp, for a lens focused at infinity.
The distinction between the two meanings is rarely made, since they have almost identical values. The value computed according to the first definition exceeds that from the second by just one focal length.
The hyperfocal distance is entirely dependent upon what level of sharpness is considered to be acceptable. The criterion for the desired acceptable sharpness is specified through the circle of confusion (COC) diameter limit. This criterion is the largest acceptable spot size diameter that an infinitesimal point is allowed to spread out to on the imaging medium (film, digital sensor, etc.).
- Source Wikipedia
Undoubtedly, "Hyperfocal Distance" is a commonly used jargon in the field of optics and photography, especially for landscape photographers. We do not want to use the smallest aperture possible simply because of diffraction. Effects of diffraction can be so severe that it outweighs the DOF increase and resulting in poor IQ instead. This is where hyperfocal distances come in to strike a balance. It can help you decide the largest aperture you can use and establish the point of focus for the given foreground subject distance while maintaining good sharpness through to the background. However, it is tedious to perform such calculations in the field.
Calculation of the "Circle of Confusion" should take consideration of Sensor/Film Size and intended print size. With the CoC value determined, you can then proceed to calculate the hyperfocal distances based on focal length and aperture size. To speed up this process, photographers often pre-calculate these parameters and print them out in form of a pocket sized table that they can refer to in the field.
I have created a simple Hyperfocal Distance Table Generator to aid those who aren't too interested in the mathematics behind all these theory. The generator bases its calculation on the indicated
1) sensor/film size
2) intended print size
3) Focal range (To adapt to different lenses)
4) Aperture range (To adapt to different lenses)
5) Aperture Adjustment Step (1, 1/2 or 1/3 stops)
6) SI unit for display (Metre or Feet)
Note: This generator is created using Microsoft Excel with VBA codes running in background. You will need to have Microsoft Excel install on your computer and "Enable Macro" while opening the file in order for the generator to work properly.
DOWNLOAD HERE (139,264 bytes)
You may also want to buy a pocket rangefinder to help you with determining distances. Cheap second hand pocket rangefinder can be found online, or if you have the money to spare, you could also get a laser rangefinder but its kinda overkill.
EDIT:
Have updated the Excel file to calculate DOF, near and far limits based on Hyperfocal Distance.
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